Jack; I think that's the same as doing a power off / power on!
To my mind this sounds very much like a corrupted database on the unit. I *think* that you could try the following; backup (say via an xcopy) the entire displayed file system while the kobo is mounted (be sure to include hidden and system files and all directories). Something like
Code:
md C:\MyKoboBackup
xcopy /e /h /k G:\ C:\MyKoboBackup
then do a logout from the Kobo account menu. This will do a delete of the database on the Kobo but will leave your ePubs on the device.
Do the resetup of the device and see how it is.
If no better, you could then just restore your backup
Code:
xcopy /e /h /k /r C:\MyKoboBackup G:\
This all assumes that G:\ is where the Kobo is mounted; change directories and locations to meet YOUR needs.
** THIS IS JUST WHAT I WOULD DO... USE AT OWN RISK **
** NO GUARANTEE TO THE APPROACH OFFERED **